Arsenal fly to Porto on Tuesday without striker Andrei Arshavin while Alexandre Song is a major doubt for the Champions League first knockout round first leg tie on Wednesday.

Arshavin may have scored only one goal in his past 12 appearances for Arsenal but with Robin van Persie still recovering from a serious ankle injury, he remains crucial to Arsène Wenger's plans.

Arshavin suffered his hamstring injury during last week's 1-0 win over Liverpool, while Song will have his fitness assessed on Tuesday. Arshavin said: "If all goes well I will get back on the pitch as early as the next Premier League match against Sunderland."

His absence means that Nicklas Bendtner should start for the first time in Europe since September.

Arsenal could be boosted by the return of striker Eduardo, back in contention after missing the last three weeks because of a hamstring problem.

Defender Thomas Vermaelen will play in Porto even though he is still struggling for full fitness a fortnight after it was feared the Belgian had fractured a leg, against Aston Villa.

The 24 year-old was carried off but it transpired that the injury was heavy bruising and, four days later, he played against Manchester United. Vermaelen said: "It turned out that I could play against United, but after that game I had some more problems, so I went for another scan.

"We could see then that there was a big bruise on the bone, and that's all. So it is painful but that can be controlled with medicine and when it is not broken, you can't do too much wrong."

Arsenal will face Brazilian striker Hulk, who returns following a domestic suspension, and although he has struggled for form this season in the League, he could be the player to ruin Wenger's Champions League aspirations again according to his club captain Bruno Alves.

The Porto defender, warned: "Hulk is a player with great ability. He's strong and has very high technical quality. He has a fabulous left foot, he's very well prepared, he's at training every day, he works very well and is very direct."

Hulk has scored only two goals in 12 league games with Porto, who are nine points behind leaders Benfica, but in the Champions League the 23 year-old has scored three in six games.

Arsenal have reached at least the quarter-finals in three of the last four years, and lost only one of their qualifying games, against Olympiakos after a place in the knockout stages had been confirmed.

Of the size of the task on Wednesday, Alves added: "Arsenal are a strong unit and a very difficult team but we can play the best football. The strategy is to cancel out their strong points. It's only with teamwork and a strong mentality we can beat Arsenal."

Alves has identified Arsenal's greatest threat. He said: "Cesc Fabregas is their most important player and we have to try to block him."